The bile-salt-stimulated lipase in human milk. Purification and characterization.
The bile-salt-stimulated lipase was purified from human whey by chromatography on heparin-Sepharose and Affi-Gel blue. The purified enzyme gave a single band with a molecular weight of 90 000 on dodecylsulphate/polyacrylamide gels and this band accounted for at least 98% of the protein on the gel. An antiserum to the purified lipase completely inhibited the enzyme activity and gave a single precipitate against human whey and purified lipase. The bile-salt-stimulated lipase was inhibited by diisopropylfluorophosphate, which bound to the purified enzyme in a molar ratio of 0.85 mol/mol. The lipase is a glycoprotein with a high content of acidic amino acid residues and an isoelectric point of around 4. Proline constitutes more than 10% of the total amino acid residues. The purified lipase has a turnover number of around 150 S-1.
D000596:Amino Acids / Q000032:analysis; D000906:Antibodies; D001647:Bile Acids and Salts / Q000494:pharmacology*; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D007118:Immunoassay; D005779:Immunodiffusion; D007531:Isoflurophate / Q000494:pharmacology; D008049:Lipase / Q000302:isolation & purification* / Q000378:metabolism; D008895:Milk, Human / Q000201:enzymology*; D008970:Molecular Weight; D011247:Pregnancy
D000596:Amino Acids; D000906:Antibodies; D001647:Bile Acids and Salts; D007531:Isoflurophate; D008049:Lipase